Ballast Water Pollution

1

Ballast Water Pollution:

The Introduction of

Non-indigenous Species

Sarah Grubs

December 19, 2003

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Used on this web site with author’s permission.
Increasingly we are seeing species of freshwater, estuarine and marine organisms sprawl out from their native regions through human mediated transport. Many of these organisms have profoundly affected the abundance and diversity of native biota in their receiving environments, often causing significant environmental and economic impacts (Cohen 1998). These species have been introduced through several mechanisms, the most common are through the movement of fouling communities on the bottom of ships, through the intentional release of aquaculture, fisher and bait species which includes a host of associated free living and parasitic organisms, through the connection of waterways via canals and through the release of organisms in ballast related materials of ships (Ruiz1997). The last of these poses the greatest environmental and economic threat with over 10 billion tons of organism infected ballast water being introduced into ports around the world each year (Reeds 1999, Zhang 1999). Shockingly, over 400 nuisance non-indigenous species (NIS) are known to be established in marine and estuarine habitats in the U.S. alone (Ruiz, Fofonoff & Hines 1999), 76 of the NIS have made repeated invasions in other ports along the coast due to intracoastal shipping (Ruiz 2000). The rate of introduction is showing no signs of leveling off; in fact NIS introduction continues to climb exponentially due to changes in shipping practices, increased eutrophication of estuarine environments and the lack of enforced regulations on the exchange of ballast water (Cohen 1998, Harvell1999, Ruiz 2000).

History

Ballast is an absolute necessity to the shipping industry; it is stored in dedicated ballast tanks that line the hull of the ship (figure 1).

Figure 1 Diagram of ballast tanks lining the hull of a cargo ship (Hallegraph & Bolch 1991)

The ballast performs several functions when cargo is absent, it controls the stability and trim of the vessel allowing the ship to steer through coastal waters and preventing it from capsizing in rough open ocean waters. It also serves to balance the stresses the ship’s hull experiences as well as increasing efficient fuel consumption (Kelly 1993, Zhang 1999).

The original forms of ballast were mainly dry, sailors would use rock, gravel and seaweed they obtained at the port they happened to reside in, to balance their ships (Reeds 1999). In fact, prior to 1870 the introduction of non-indigenous species occurred mainly through hull fouling of the wooden ships (Ruiz 1997). Today very few organisms are carried into foreign ports on the hulls of ships due to the increased speed, anti-fouling paints and low port residency times. Ballast took a revolutionary turn at the end 19th century with the creation of steel ships. This evolution allowed for the use of water as ballast which took less time and man power to fill the tanks, it also created a new more efficient method of NIS introduction (Kelly 1993).

Ballast Today

Today the movement of ballast water between ports is claimed to be the largest single vector in the introduction of NIS (Aliotta 2001; Carlton 1985; Dickman 1999; Lavoie 1999; Kelly 1993; Ruiz 2000; Zhang 1999). The increased rate of introduction is attributed to the increase in size and number of cargo ships, the increase in their speed and the increase in the eutrophication of estuaries (Zhang 1999). Ballast is most frequently taken on while ships are in port, these ports lie in bays and estuaries that are laden with potentially pathogenic diatoms, dinoflagellates, bacteria such as Vibrio cholerae, viruses and the larvae of various crustaceans, bivalves and vertebrates. This water is then transported inter and intra coastally where it is then discharged upon arrival in a foreign port (Carlton 1996). The success of a ballast-mediated invasion depends on several factors, an organism must first survive the voyage; for species such as Clostridium, dinoflagellates and diatoms this is an easy task due to their ability to form spores and cysts (Kelly 1993). Upon their release from the ballast tank they may encounter problems such as pump effect in which they are damaged via the pump in the discharge of the water. If they are discharge unharmed they must then adapt and establish in their new environment in numbers significant enough to reproduce (Lavoie 1999). This task is not impossible when you consider that San Francisco Bay alone has experienced the establishment of 234 known NIS (Carlton 1990). The nature of the cargo shipping industry creates a habitat that gets regular inoculations of water from specific regions on a frequent basis (Lavoie 1999). Bulk cargo ships are normally contracted to carry cargo for only one leg of each voyage which requires them to travel “in ballast” the other half of the time. Countries that have a large amount of export therefore stand to be the recipient of the majority of foreign ballast water as is the case with the United States and Australia (Kelly 1993). Australia receives 60 million tons of ballast water every year, most of which is from Japan (Hallegraeff & Bolch 1992) while the United States receives over 79 million tons of ballast water yearly from around the world (Ruiz 1997). The frequency and intensity of ballast water discharge in these countries and around the world has resulted the introduction of hundreds of organisms that have had huge economic impacts. The U.S. alone has an estimated economic impact of $100 billion. (Ruiz 2001).

The Extent of the Problem

Zebra Mussel, Dreissena polymorpha

The Zebra mussel was first discovered in the Great Lakes in the 80’s. It was introduced from the Black and Caspian Sea where it lives in normal numbers and in balance with its environment (Carlton 1996). Since its introduction it has successfully spread through connected water ways from the Great Lakes to Arkansas (Figure 2) (Reeds 1999).

Figure 2 Map of the spread of the Zebra Mussel throughout the

United States. Red indicates highest concentrations

of mussels (

A female zebra mussel is able to lay 1 million eggs in one summer. Once hatched the larvae are microscopic and are able to travel long distances. Today populations of zebra mussels have reached a staggering 70,000 individuals per meter squared (Reeds 1999). The mussels have had huge ecological and economic impacts in the U.S. They occur in such significant numbers that they clog intake pipes to many facilities and coat the hulls of any ship in their vicinity. More importantly they have wreaked havoc on the environment through the disruption of the base of the food chain. These mussels have effectively filtered 80% of the phytoplankton biomass in the habitats they infest. This has led to greater light penetration altering the composition and density of the vegetation in lakes all along the Mississippi (

Gymnodinium catenatum

Hallegraeff and Bolch have done extensive research on species introduced to Australia. Australian economy relies heavily on the export of raw materials such as coal, grain, iron ore and wheat. The ships export these commodities in one direction, returning with their ballast tanks full of water from foreign ports. (Hallegraeff & Bolch 1991). In the study of 343 ships entering 18 Australian ports they discovered that 65% of the ships carried sediment with non-indigenous diatoms and 50% of the ships contained the resting spores of non-indigenous dinoflagellates, one particular ship had apparently ballasted during a dinoflagellate bloom and contained over 300 million species of a dinoflagellate known to cause paralytic shellfish poisoning (Hallegraeff & Bolch 1992). The regular inoculation of these species has created dinoflagellate cyst beds in and around Australia. In 1986 and again in 1991 toxic blooms of these species caused the closure of 15 shellfish farms for periods of up to 6 months. These benthic cyst beds are now widespread throughout Australia and Tasmania making what has been a family business for century’s economic time bombs (Hallegraeff & Bolch 1992).

Infectious Salmon Anemia

Infectious salmon anemia virus (ISAV) is an emerging disease that has caused severe damage to the salmon-farming industry. This virus causes lesions on the gills of salmon that inhibits the fishes’ respiration (Figure 3).

Figure 3 A lesion produced on the gill of salmon

infected by infectious salmon anemia

(

ISAV was discovered in Norway in 1984, it is a virulent strain of virus that has adapted to the intensive aquacultural practices. In 1998 it was introduced to Scotland in the ballast water of well boats. The well boats had foolishly ballasted next to the processing plants effluent which was contaminated with the blood of infected salmon. ISAV has since spread to Canada, the Faroe Islands and in 2000 it was sadly reported in Maine. Although the economic impact in the United States is not yet estimated, ISAV has already caused over $60 million in damage a year in other countries (Murray, Smith & Stagg 2002).

Current National and International Policy

The United States has done relatively little in the protection of our estuaries in regard to NIS introduction. The mid-ocean exchange of ballast water is currently the only suggested management strategy in the prevention of NIS. This consists of ships exchanging the eutrophic port water for open ocean water when they are in waters greater than 2000m deep and outside the Economic Exclusive Zone (EEZ), a 200 mile strip of ocean surrounding all United States territory (Aliotta 2001). In contrast to coastal waters, mid-ocean waters are poor in nutrients and contain relatively few organisms. The organisms present in open-ocean waters are oligotrophic in nature and in theory have a low likelihood of being able to survive in the nutrient rich waters of ports (Zhang 1999). Until 1990, the U.S. did not have any written restrictions on ballast water. The Non-indigenous Aquatic Nuisance Prevention and Control Act of 1990 was the first attempt at regulating ballast exchange. This act required that all ships entering the Great Lakes undergo ballast water exchange prior to crossing the EEZ. ( The National Invasive Species Act (NISA) of 1996 reauthorized and amended the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 to include a required a mandatory ballast water report be filed with all ports in the U.S. declaring the intent and treatment of any ballast water on board. It also requested the voluntary compliance of mid-ocean exchange prior to entering U.S. waters (Dickman 1999). These acts are voluntary and provide little in the way of incentive to the shipping industry. Even if the acts requested mandatory exchange, enforcement and monitoring (which requires a simple salinity test) would not be feasible due to the lack of money and the shear number of ships that entering U.S. ports daily. This is fact is unfortunately evident when one observes to what extent compliance has been less than desirable; figure 4 shows the points of exchange within the United States from 1999 to 2001. The majority of ballast water exchange has occurred within the EEZ (Ruiz 2001).

Figure 4 Reported ballast water exchange locations for individual ballast tanks

on vessels arriving to the United States between July 1999 and

June 2001. Gray shading indicated EEZ (Ruiz 2001).

In a study conducted by Ruiz of the 28,988 foreign arrivals that submitted reports (which consequently was only 30% of all ships arriving) 73.6% indicated no intention to discharge ballast water in the U.S., 12.9% declared no open ocean exchange of ballast water prior to discharge in port and 13% declared only some degree of open-ocean exchange prior to discharge in port. Of the 73.6% of vessels claiming no intent to discharge in U.S. almost all of them had ballast water on board (Ruiz 2001). Conducted interviews of ships officers confirmed that while some ships practice ballasting and de-ballasting procedures, all ships routinely discharge some volume of ballast water and sediments into local waters (Kelly 1993). It is apparent that the acts passed to regulate NIS introduction have been met with less than little enthusiasm by the shipping industry. The lack of enthusiasm is most likely due to the problems that mid-ocean exchange pose. Exchange of ballast water is simply not feasible for ships in rough water due to the increased vulnerability of ships without ballast. In addition to the integrity of ships, exchange is more frequently not performed due to itinerary and shipping schedules. The shipping industry is of course; entirely driven by financial gain and failure to arrive to port on time can result in the loss of a contract for an entire shipping fleet (Ruiz 2001).

All of the shipping industry oppositions aside, the most alarming problem with open-ocean ballast water exchange is not compliance but the actual effectiveness of the management itself. The effectiveness of ballast water exchange as a national management strategy is seriously disputed. Theoretically for a ballast tank in which all organisms are homogenously distributed throughout the water column, the current method for exchange would be 95-99% effective as claimed by the National Clearinghouse for Ballast Water. Many of the leading scientists in ballast water management have conducted studies in the effectiveness of open-ocean ballast water exchange in which their findings have given a much more dismal percentage of effectiveness for open ocean ballast exchange. In 1999 Zhang and Dickman conducted tests on the effectiveness of exchange based on vessel type. They discovered that many of the older vessels were not efficient in removing the water and sediment located near the bottom of ships. The ships coming out of Manzanillo, Mexico had an open-ocean exchange of only 48% effectiveness, upon closer examination it was discovered that many of the diatoms and dinoflagellates in the ballast tank after exchange were coastal species which leads to the conclusion that a percentage of the coastal water was not exchanged (Dickman & Zhang 1999). Ballast tank gauges confirmed the suspicion indicating that during exchange there is typically a small amount of water 1-5% that is retained in the bottom of the tank. This water is of particular concern because in contains sediment that has settled to the bottom, this sediment in turn contains cysts, spores and dormant cells of organisms which leads to the 1-5% of water left having an unusually high density of organisms (Zhang & Dickman 1999). As a marine biologist with a microbiology background I can comfortably say that given the asexual nature of many of these organisms this would be more than sufficient to induce rapid proliferation upon introduction to a compatible habitat.

Hallegraeff and Bolch confirmed these findings in their 1992 study in which 14 of the 32 vessels they examined contained significant numbers of dinoflagellate cysts even after mid-ocean exchange (Hallegraeff & Bolch 1992).

The sediment contained in ballast tanks is not currently under any type of mandate or regulation in the United States and yet it poses every bit as much a considerable threat as its associated ballast water. Current management for the shipping industry simply involves the routine maintenance of the tanks in which the sediment is collected to be disposed of later. Kelly performed research into the fate of these sediments in the state of Washington. She discovered that of all the ships that were sampled the sediment taken from the hold ranged from 600-1900 liters. When questioned, 4 of 6 officers stated that sediments would remain stored on deck until the ship was outside harbor waters before they would be dumped. Her personal observations were that “a significant amount of these sediments were discharged into port waters during de-ballasting of water, cleaning of the hold and subsequent clean of the ship decks” (Kelly 1993). With the continuing increase in the rate of introduction of NIS it is obvious that existing management is not sufficient, we must then look to other forms of management.

The Future of Ballast Water Management

Several other forms of ballast water purification are currently being researched by scientists around the world. Some of the most promising include; heat treatment, Ozone treatment, and a method that I have personally been researching Electro- Ionization. For a ballast water treatment technology to be approved by the National Ballast Water Clearinghouse it must prove to be more effective than open-ocean exchange ( Other criterion the treatment system must fulfill is to be safe to the ship and crew, environmentally friendly, compatible with ship design and operations and cost effective (Aliotta 2001). The U.S. Fisheries and Wildlife Services and National Oceanic and Atmospheric Administration (NOAA’s) National Sea Grant College Program have taken the first step in promoting the development of these new technologies through the funding of efforts to advance the research and technology of secondary forms of ballast water treatment (Cangelosi 1999).